Bronstedacidic ionic liquid 3-methyl-1-sulphonic acid imidazolium chloride {[Msim]Cl} is utilized as a highly efficient, inexpensive, mild and green catalyst for the synthesis of β-acetamido ketones by the one-pot multi-component coupling between acetophenones, arylaldehydes, acetonitrile and acetyl chloride at room temperature. Under these conditions, the title compounds are produced in high to excellent yields and in relatively short reaction times. In addition, this method is superior to reported methods, for the synthesis of β-acetamido ketones and is applicable for the synthesis of tris(β-acetamido ketone).